x86/kprobes: Fix crash when probing CS CALL instructionsgrafted

When using eBPF to probe CS CALL instructions within a function,
a crash can be triggered.

The eBPF tool probes offset 257 of the __hrtimer_run_queues()
function:

<__hrtimer_run_queues+249>:  nopl   0x0(%rax,%rax,1)
<__hrtimer_run_queues+254>:  mov    %r14,%rdi
<__hrtimer_run_queues+257>:  cs call <__x86_indirect_thunk_r12>
<__hrtimer_run_queues+263>:  mov    %eax,%r12d
<__hrtimer_run_queues+266>:  xchg   %ax,%ax
<__hrtimer_run_queues+268>:  mov    %r13,%rdi

Which triggers this crash:

  BUG: unable to handle page fault for address: 00000000000f41c9
  #PF: supervisor write access in kernel mode
  #PF: error_code(0x0002) - not-present page
  PGD 0 P4D 0
  Oops: 0002 [#1] SMP NOPTI
  CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P
  RIP: 0010:__hrtimer_run_queues+0x106/0x230

Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is
at the 6th byte of the above CS CALL instruction. Since the CS CALL
instruction occupies 6 bytes, the exception occurred in the middle of that
call instruction.

The root cause is that when using eBPF tools to probe in the middle of a
function, a kprobe with INT3 is used as the underlying implementation.

During single-step emulation of the original CALL instruction,
int3_emulate_call() assumes that the probed CALL instruction is 5 bytes
long. However, the actual CS-prefixed CALL instruction occupies 6 bytes,
so it constructs an incorrect exception return address. When the CPU
returns from the kprobe handler, the next instruction to be executed is at
the address of the last byte of that CS CALL instruction. Coincidentally,
starting from that address, the CPU fetches and decodes a completely
different instruction, which ultimately triggers a kernel crash.

Fix the issue by using the actual instruction length obtained from
the instruction decoder when constructing the exception return
address, rather than relying on the hardcoded CALL_INSN_SIZE macro.

[ mingo: Refined the changelog ]

Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jinke Han <jinkehan@didiglobal.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000

3 files changed, 190 insertions, 0 deletions

diff --git a/drivers/phy/sophgo/Kconfig b/drivers/phy/sophgo/Kconfig
new file mode 100644
index 000000000..2c943bbe1
--- /dev/null
+++ b/drivers/phy/sophgo/Kconfig
@@ -0,0 +1,19 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Phy drivers for Sophgo platforms
+#
+
+if ARCH_SOPHGO || COMPILE_TEST
+
+config PHY_SOPHGO_CV1800_USB2
+	tristate "Sophgo CV18XX/SG200X USB 2.0 PHY support"
+	depends on MFD_SYSCON
+	depends on USB_SUPPORT
+	select GENERIC_PHY
+	help
+	  Enable this to support the USB 2.0 PHY used with
+	  the DWC2 USB controller in Sophgo CV18XX/SG200X
+	  series SoC.
+	  If unsure, say N.
+
+endif # ARCH_SOPHGO || COMPILE_TEST
diff --git a/drivers/phy/sophgo/Makefile b/drivers/phy/sophgo/Makefile
new file mode 100644
index 000000000..318060661
--- /dev/null
+++ b/drivers/phy/sophgo/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_PHY_SOPHGO_CV1800_USB2)	+= phy-cv1800-usb2.o
diff --git a/drivers/phy/sophgo/phy-cv1800-usb2.c b/drivers/phy/sophgo/phy-cv1800-usb2.c
new file mode 100644
index 000000000..6fe846534
--- /dev/null
+++ b/drivers/phy/sophgo/phy-cv1800-usb2.c
@@ -0,0 +1,169 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2025 Inochi Amaoto <inochiama@outlook.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/bitfield.h>
+#include <linux/debugfs.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/phy/phy.h>
+#include <linux/regmap.h>
+#include <linux/spinlock.h>
+
+#define REG_USB_PHY_CTRL		0x048
+
+#define PHY_VBUS_POWER_EN		BIT(0)
+#define PHY_VBUS_POWER			BIT(1)
+#define PHY_ID_OVERWRITE_EN		BIT(6)
+#define PHY_ID_OVERWRITE_MODE		BIT(7)
+#define PHY_ID_OVERWRITE_MODE_HOST	FIELD_PREP(BIT(7), 0)
+#define PHY_ID_OVERWRITE_MODE_DEVICE	FIELD_PREP(BIT(7), 1)
+
+#define PHY_APP_CLK_RATE		125000000
+#define PHY_LPM_CLK_RATE		12000000
+#define PHY_STB_CLK_RATE		333334
+
+struct cv1800_usb_phy {
+	struct phy	*phy;
+	struct regmap	*syscon;
+	spinlock_t	lock;
+	struct clk	*usb_app_clk;
+	struct clk	*usb_lpm_clk;
+	struct clk	*usb_stb_clk;
+	bool		support_otg;
+};
+
+static int cv1800_usb_phy_set_mode(struct phy *_phy,
+				   enum phy_mode mode, int submode)
+{
+	struct cv1800_usb_phy *phy = phy_get_drvdata(_phy);
+	unsigned int regval = 0;
+	int ret;
+
+	dev_info(&phy->phy->dev, "set mode %d", (int)mode);
+
+	switch (mode) {
+	case PHY_MODE_USB_DEVICE:
+		regval = PHY_ID_OVERWRITE_EN | PHY_ID_OVERWRITE_MODE_DEVICE;
+		regmap_clear_bits(phy->syscon, REG_USB_PHY_CTRL, PHY_VBUS_POWER);
+		break;
+	case PHY_MODE_USB_HOST:
+		regval = PHY_ID_OVERWRITE_EN | PHY_ID_OVERWRITE_MODE_HOST;
+		regmap_set_bits(phy->syscon, REG_USB_PHY_CTRL, PHY_VBUS_POWER);
+		break;
+	case PHY_MODE_USB_OTG:
+		if (!phy->support_otg)
+			return 0;
+
+		ret = regmap_read(phy->syscon, REG_USB_PHY_CTRL, &regval);
+		if (ret)
+			return ret;
+
+		regval = FIELD_GET(PHY_ID_OVERWRITE_MODE, regval);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return regmap_update_bits(phy->syscon, REG_USB_PHY_CTRL,
+				  PHY_ID_OVERWRITE_EN | PHY_ID_OVERWRITE_MODE,
+				  regval);
+}
+
+static int cv1800_usb_phy_set_clock(struct cv1800_usb_phy *phy)
+{
+	int ret;
+
+	ret = clk_set_rate(phy->usb_app_clk, PHY_APP_CLK_RATE);
+	if (ret)
+		return ret;
+
+	ret = clk_set_rate(phy->usb_lpm_clk, PHY_LPM_CLK_RATE);
+	if (ret)
+		return ret;
+
+	return clk_set_rate(phy->usb_stb_clk, PHY_STB_CLK_RATE);
+}
+
+static const struct phy_ops cv1800_usb_phy_ops = {
+	.set_mode	= cv1800_usb_phy_set_mode,
+	.owner		= THIS_MODULE,
+};
+
+static int cv1800_usb_phy_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device *parent = dev->parent;
+	struct cv1800_usb_phy *phy;
+	struct phy_provider *phy_provider;
+	int ret;
+
+	if (!parent)
+		return -ENODEV;
+
+	phy = devm_kmalloc(dev, sizeof(*phy), GFP_KERNEL);
+	if (!phy)
+		return -ENOMEM;
+
+	phy->syscon = syscon_node_to_regmap(parent->of_node);
+	if (IS_ERR_OR_NULL(phy->syscon))
+		return -ENODEV;
+
+	phy->support_otg = false;
+
+	spin_lock_init(&phy->lock);
+
+	phy->usb_app_clk = devm_clk_get_enabled(dev, "app");
+	if (IS_ERR(phy->usb_app_clk))
+		return dev_err_probe(dev, PTR_ERR(phy->usb_app_clk),
+			"Failed to get app clock\n");
+
+	phy->usb_lpm_clk = devm_clk_get_enabled(dev, "lpm");
+	if (IS_ERR(phy->usb_lpm_clk))
+		return dev_err_probe(dev, PTR_ERR(phy->usb_lpm_clk),
+			"Failed to get lpm clock\n");
+
+	phy->usb_stb_clk = devm_clk_get_enabled(dev, "stb");
+	if (IS_ERR(phy->usb_stb_clk))
+		return dev_err_probe(dev, PTR_ERR(phy->usb_stb_clk),
+			"Failed to get stb clock\n");
+
+	phy->phy = devm_phy_create(dev, NULL, &cv1800_usb_phy_ops);
+	if (IS_ERR(phy->phy))
+		return dev_err_probe(dev, PTR_ERR(phy->phy),
+			"Failed to create phy\n");
+
+	ret = cv1800_usb_phy_set_clock(phy);
+	if (ret)
+		return ret;
+
+	phy_set_drvdata(phy->phy, phy);
+	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+
+	return PTR_ERR_OR_ZERO(phy_provider);
+}
+
+static const struct of_device_id cv1800_usb_phy_ids[] = {
+	{ .compatible = "sophgo,cv1800b-usb2-phy" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, cv1800_usb_phy_ids);
+
+static struct platform_driver cv1800_usb_phy_driver = {
+	.probe = cv1800_usb_phy_probe,
+	.driver = {
+		.name = "cv1800-usb2-phy",
+		.of_match_table = cv1800_usb_phy_ids,
+	 },
+};
+module_platform_driver(cv1800_usb_phy_driver);
+
+MODULE_AUTHOR("Inochi Amaoto <inochiama@outlook.com>");
+MODULE_DESCRIPTION("CV1800/SG2000 SoC USB 2.0 PHY driver");
+MODULE_LICENSE("GPL");